The code in spamass-milter.cpp that tries to create a Sendmail-compatible header was broken and generated a header that was incorrectly parsed by SpamAssassin. This is mostly fixed now apart from the space that needs adding prior to the "(" between macro_j and macro_v. https://savannah.nongnu.org/bugs/index.php?17178 http://bugs.debian.org/510665 http://bugzilla.redhat.com/496763 diff -up spamass-milter-0.3.2/spamass-milter.cpp.rcvd spamass-milter-0.3.2/spamass-milter.cpp --- spamass-milter-0.3.2/spamass-milter.cpp.rcvd 2011-02-15 10:46:55.000000000 +0000 +++ spamass-milter-0.3.2/spamass-milter.cpp 2011-02-15 10:50:25.538111680 +0000 @@ -966,7 +966,7 @@ mlfi_envrcpt(SMFICTX* ctx, char** envrcp assassin->output((string) "Received: from "+macro_s+" ("+macro__+")\r\n\t"+ - "by "+macro_j+"("+macro_v+"/"+macro_Z+") with "+macro_r+" id "+macro_i+";\r\n\t"+ + "by "+macro_j+" ("+macro_v+"/"+macro_Z+") with "+macro_r+" id "+macro_i+";\r\n\t"+ macro_b+"\r\n\t"+ "(envelope-from "+assassin->from()+")\r\n");